Stay-bolt for boilers.



Aiforney Patented D66. 26,1916.

7 INVENTOR E. I. DODDS.

STAY BOLT FOR BOILERS.

APPUCATION FILED OCT. 19, 1914. 1,209,946.

Fill l Vvvv vv WIT ESSES rn rare.

COMPANY, OF PITTSBURGH, PENNSYLVANIA.

STAY-BOLT FOR BOILERS.

Specification of Letters Patent. v Patented D60. 26, 1916.

Application filed oetoberiaiem. Serial No. 367,412

To all whom it may concern:

Be it known that I, ETHAN I, DoDDs, of Pittsburgh, in the county ofAllegheny and State of Pennsylvania, have invented certain new anduseful Improvements in Stay- Bolts for Boilers; and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the .art to which itappertains to make and use the same.

My invention relates to an improvement in stay bolts for boilers, theobject being to provide a bolt that will be free to yield or vibrate andaccommodate itself to the lateral twisting and torsional movement of theboiler sheets, but of suflicient rigidity to prevent any collapsing ofthe sheets and any bending or twisting of the bolt while being applied.

With these objects in view my invention consists in the details ofconstruction as will be more fully explained and pointed out in theclaims.

In the accompanying drawings, Figure 1 is a blank; Fig. 2 shows theblank after it has been slotted; Fig. 3 is a view in cross section ofthe bolt; Fig. 4: is a view of the completed bolt; Fig. 5 is a view incross section of same; Fig. 6 is a view in elevation of the completebolt, and Figs. 7, 8 and 9 are views in cross section showing modifiedarrangement of slots.

Heretofore bolts designed to respond to the vibration and the lateralmovements of boiler sheets have been slotted longitudinally all the waythrough and then twisted spirally, and in other instances they have beenmade of two half round sections twisted and threaded.

With such constructions the bolts will buckle and bend under compressivestrains when applying them to the sheets and particularly so in theevent the threads should bind.

In constructing the bolts I take a blank 1 of stay bolt iron and punchtherein a series of comparatively short slots 2, the latter being out ofline and preferably arranged spirally around the shank of the bolt fromthe head 3 to the threaded end 4. The depth of these slots may vary, butthey extend past the center or neutral axis of the bolt, stopping moreor less short of the opposite side so as to leave the bottom of theslots closed.

It is also desirable that the ends of the adjacent slots beapproximately in the same plane or overlapping so that the flexingmovement of the bolt may be continuous from the head to the threaded endof the shank.

After the shank has been slotted, the dilation caused by the slottingtool is reduced by dies or other suitable tools so as to close the wallsthereof together, after which the head 8 is formed and the end 4:threaded. If desired the shank may be twisted as in Fig. 6 so as toimpart a spiral twist to the slots. Instead of slotting it as abovedescribed, it may be slotted at the opposite sides as shown in Fig. 8,the slots of each pair being in the same plane and stopping short of thecenter so as to leave a thin web between the slots, or the slots mayoverlap as in Fig. 9, or be disposed diagonally as in Fig. 7

By thus constructing the bolts they are as rigid against longitudinalcompression or pulling stresses as a rigid bolt, but are comparativelyfree to turn under torsional strains and lateral vibrations, hence arespecially adapted for use in connecting boiler sheets where thevibration or torsional stresses frequently rupture the bolt.

I make no claim in this application to a single slot passing part waythrough the bolt, the shank being twisted to impart a spiral twist tothe single slot; nor to a bar having slots at opposite sides andextending throughout the length of the shank, the shank being twisted toimpart a spiral twist to the slots. as these features are covered by myapplications serially numbered 867,413; 867,410 and 867,411.

It is evident that many slight changes might be resorted to in therelative arrange ment of parts shown and described and in the sequenceof the steps of the operation without departing from the spirit andscope of my invention as defined by the appended claims. Hence I wouldhave it understood that I do not wish to confine myself to the exactconstruction and arrangement of parts shown and described, but

Having fully described my invention what I claim as new and desire tosecure by Letters-Patent, is

1. A stay bolt having a series of slots, said slots extendinglongitudinally and said series arranged spirally around the bolt, the

said slots extending only part Way through In testimony whereof, I havesigned this the bolt. specification in the presence of tWo sub- 2. Astay bolt having a series of slots said scribing Witnesses.

slots extending longitudinally and said se ETHAN I. DODDS.

5 ries arranged in spiral form, the said slots Witnesses:

passing the center of the bolt shank but not B. E. D. GAFFORD, passingthrough the same. EDWIN S. RYCE.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents,

Washington, D. G.

